In the 1930 census for Bruce, Macomb Co, MI, there is a John and Earl Middleditch (ages 5 and 6) living in the household of Adelia Ferguson (age 55). This looks like it might be a foster situation.
A birth location of Imlay City, Lapeer Co, MI suggests a relationship to the Perry & Myra Middleditch family who were living there in 1910 and 1920. Since Perry was 72 in 1920, his children (or grandchildren) are the ones that I would look at as possible parents for John and Earl.
The 1910 census also lists Perry and Myra Middleditch in Imlay City and shows that Myra had four children, three of whom were still alive that year. These were apparently out on there own at that point.
Other census years name two of the children, Dennis Franklin Middleditch (age 2 in 1880) and Jenni Middleditch (11 years old in 1900). The census is of no help with the other two.
Perry Middleditch was the son of Paolo Middleditch and Ann Eliza Stafford. Paolo was the son of Matthew Middleditch. Ann Eliza was the daughter of Thomas Stafford.
I hope this helps. There is much more work to be done to either confirm them or eliminate them as possibilities.